1. Field of the Invention
The present invention relates to a continuous kneading machine in which process for uniformly mixing and kneading various kinds of materials in a state of liquid, viscous substance or powder is performed.
2. Prior Art
FIG. 14 shows one of kneading machines heretofore known.
This known kneading machine is provided with at least two pairs of lense-shaped paddles (b), (c) respectively arranged in a cylindrical body (a) formed of two partially crossover circles in section so as to engage with each other and rotate in the same one direction within the cylindrical body (a). When rotating the paddles (b), (c), a self-cleaning is performed in such a manner that internal wall of the cylindrical body (a) and external surface of the baddles (b), (c) are scraped. At the same time, as a result of continuous change in sectional area of a space formed between the paddles (b), (c) engaged each other and the internal wall of the body (a) to be occupied by the treated materials, compression and expansion of the materials takes places repeatedly, resulting in mixing and kneading of the materials.
There exist, however, following problems to be solved in the mentioned conventional kneading machine:
1) Referring to FIG. 14, when rotating the two paddles (b), (c) in the same one direction indicated the arrows, it happens that a material held in a space (d) (hereinafter referred to as "material space") to be filled with the material put between the paddles (b), (c) and the body (a) moves leftward, while a material held in another material space (e) moves counterclockwise downward, and therefore the materials are difficult to encounter each other. In other words, even if the material held in the material space (d) moves after the material held in the material space (e) to catch it up, the latter material held in the material spcae (e) cannot be caught but moves away. Likewise, on the underside, a material held in the material space (f) moves counterclockwise downward, while a material held in the material space (g) moves rightward, and the materials are difficult to encounter each other. As a result, no effective kneading takes place.
2) So long as the two paddles (b), (c) are rotated at equal speed, there is a possibility of encountering and mixture only between the limited and unchanged part of the materials every rotation, no matter how rotation of the two paddles is repeated. This is another problem resulting in insufficient kneading.
3) Because of little change in the sectional area of respective material spaces, no efficient kneading takes place.
4) Since the pair of paddles (b), (c) rotate in contact with each other for the purpose of self-cleaning, one end of either paddle is always in contact with another paddle, hence there arises a further problem of local or partial abrasion of such contact portion, as compared with other portions on the paddles.